We report magnetic and electrical measurements of Nb Josephson junctions with strongly ferromagnetic barriers of Co, Ni and Ni80Fe20 (Py). All these materials show multiple oscillations of critical current with barrier thickness implying repeated 0-π phase-transitions in the superconducting order parameter. We show in particular that the Co barrier devices can be accurately modelled using existing clean limit theories and so that, despite the high exchange energy (309 meV), the large IcRN value in the π-state means Co barriers are ideally suited to the practical development of superconducting π-shift devices.

We report a systematic study of Nb/ferromagnet ͑FM͒/Nb trilayer structures in which the FM layer is one of the strong ferromagnets Co, Fe, Ni, and Ni 80 Fe 20 ͑Py͒. Accurate control of the FM layer thickness has enabled detailed studies of the magnetic and transport properties in the superconducting state. In all cases, we estimate the thickness of the magnetic dead layer and the exchange energies of the ferromagnetic layers; in doing so, we demonstrate inconsistencies between the exchange energies derived elsewhere from superconductor ͑S͒/FM bilayer experiments and from S/FM/S junction measurements compared to their bulk Curie temperatures, which may hint at further complexity in the underlying physics. We show results in support of a recent publication ͓J. W. A Robinson et al., Phys. Rev. Lett. 97, 177003 ͑2006͔͒, focus in detail on a single 0-phase transition, and show evidence for the appearance of a second harmonic in the current-phase relation at the minimum of the critical current.Thin films of Nb/ Co/ Nb, Nb/Py/Nb, Nb/ Ni/ Nb, and Nb/ Fe/ Nb were prepared on thermally oxidized ͑100͒ Si substrates with a 250 nm oxide layer on the surface in an PHYSICAL REVIEW B 76, 094522 ͑2007͒

Additively manufactured lattice structures are popular due to their desirable properties, such as high specific stiffness and high surface area, and are being explored for several applications including aerospace components, heat exchangers and biomedical implants. The complexity of lattices challenges the fabrication limits of additive manufacturing processes and thus, lattices are particularly prone to manufacturing defects. This paper presents a review of defects in lattice structures produced by powder bed fusion processes. The review focuses on the effects of lattice design on dimensional inaccuracies, surface texture and porosity. The design constraints on lattice structures are also reviewed, as these can help to discourage defect formation. Appropriate process parameters, post-processing techniques and measurement methods are also discussed. The information presented in this paper contributes towards a deeper understanding of defects in lattice structures, aiming to improve the quality and performance of future designs.